/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
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 *
 *
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 *
 *
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 *
 *
 *
 *
 */

package javax.swing;

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.*;
import java.beans.Transient;
import java.util.Vector;
import java.util.Enumeration;

import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

import javax.swing.event.*;
import javax.swing.border.Border;
import javax.swing.plaf.*;
import javax.accessibility.*;

/**
 * An implementation of a menu bar. You add <code>JMenu</code> objects to the
 * menu bar to construct a menu. When the user selects a <code>JMenu</code>
 * object, its associated <code>JPopupMenu</code> is displayed, allowing the
 * user to select one of the <code>JMenuItems</code> on it.
 * <p>
 * For information and examples of using menu bars see
 * <a
 * href="https://docs.oracle.com/javase/tutorial/uiswing/components/menu.html">How to Use Menus</a>,
 * a section in <em>The Java Tutorial.</em>
 * <p>
 * <strong>Warning:</strong> Swing is not thread safe. For more
 * information see <a
 * href="package-summary.html#threading">Swing's Threading
 * Policy</a>.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans&trade;
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 * <p>
 * <strong>Warning:</strong>
 * By default, pressing the Tab key does not transfer focus from a <code>
 * JMenuBar</code> which is added to a container together with other Swing
 * components, because the <code>focusTraversalKeysEnabled</code> property
 * of <code>JMenuBar</code> is set to <code>false</code>. To resolve this,
 * you should call the <code>JMenuBar.setFocusTraversalKeysEnabled(true)</code>
 * method.
 *
 * @author Georges Saab
 * @author David Karlton
 * @author Arnaud Weber
 * @beaninfo attribute: isContainer true description: A container for holding and displaying menus.
 * @see JMenu
 * @see JPopupMenu
 * @see JMenuItem
 */
@SuppressWarnings("serial")
public class JMenuBar extends JComponent implements Accessible, MenuElement {

  /**
   * @see #getUIClassID
   * @see #readObject
   */
  private static final String uiClassID = "MenuBarUI";

  /*
   * Model for the selected subcontrol.
   */
  private transient SingleSelectionModel selectionModel;

  private boolean paintBorder = true;
  private Insets margin = null;

  /* diagnostic aids -- should be false for production builds. */
  private static final boolean TRACE = false; // trace creates and disposes
  private static final boolean VERBOSE = false; // show reuse hits/misses
  private static final boolean DEBUG = false;  // show bad params, misc.

  /**
   * Creates a new menu bar.
   */
  public JMenuBar() {
    super();
    setFocusTraversalKeysEnabled(false);
    setSelectionModel(new DefaultSingleSelectionModel());
    updateUI();
  }

  /**
   * Returns the menubar's current UI.
   *
   * @see #setUI
   */
  public MenuBarUI getUI() {
    return (MenuBarUI) ui;
  }

  /**
   * Sets the L&amp;F object that renders this component.
   *
   * @param ui the new MenuBarUI L&amp;F object
   * @beaninfo bound: true hidden: true attribute: visualUpdate true description: The UI object that
   * implements the Component's LookAndFeel.
   * @see UIDefaults#getUI
   */
  public void setUI(MenuBarUI ui) {
    super.setUI(ui);
  }

  /**
   * Resets the UI property with a value from the current look and feel.
   *
   * @see JComponent#updateUI
   */
  public void updateUI() {
    setUI((MenuBarUI) UIManager.getUI(this));
  }


  /**
   * Returns the name of the L&amp;F class that renders this component.
   *
   * @return the string "MenuBarUI"
   * @see JComponent#getUIClassID
   * @see UIDefaults#getUI
   */
  public String getUIClassID() {
    return uiClassID;
  }


  /**
   * Returns the model object that handles single selections.
   *
   * @return the <code>SingleSelectionModel</code> property
   * @see SingleSelectionModel
   */
  public SingleSelectionModel getSelectionModel() {
    return selectionModel;
  }

  /**
   * Sets the model object to handle single selections.
   *
   * @param model the <code>SingleSelectionModel</code> to use
   * @beaninfo bound: true description: The selection model, recording which child is selected.
   * @see SingleSelectionModel
   */
  public void setSelectionModel(SingleSelectionModel model) {
    SingleSelectionModel oldValue = selectionModel;
    this.selectionModel = model;
    firePropertyChange("selectionModel", oldValue, selectionModel);
  }


  /**
   * Appends the specified menu to the end of the menu bar.
   *
   * @param c the <code>JMenu</code> component to add
   * @return the menu component
   */
  public JMenu add(JMenu c) {
    super.add(c);
    return c;
  }

  /**
   * Returns the menu at the specified position in the menu bar.
   *
   * @param index an integer giving the position in the menu bar, where 0 is the first position
   * @return the <code>JMenu</code> at that position, or <code>null</code> if if there is no
   * <code>JMenu</code> at that position (ie. if it is a <code>JMenuItem</code>)
   */
  public JMenu getMenu(int index) {
    Component c = getComponentAtIndex(index);
    if (c instanceof JMenu) {
      return (JMenu) c;
    }
    return null;
  }

  /**
   * Returns the number of items in the menu bar.
   *
   * @return the number of items in the menu bar
   */
  public int getMenuCount() {
    return getComponentCount();
  }

  /**
   * Sets the help menu that appears when the user selects the
   * "help" option in the menu bar. This method is not yet implemented
   * and will throw an exception.
   *
   * @param menu the JMenu that delivers help to the user
   */
  public void setHelpMenu(JMenu menu) {
    throw new Error("setHelpMenu() not yet implemented.");
  }

  /**
   * Gets the help menu for the menu bar.  This method is not yet
   * implemented and will throw an exception.
   *
   * @return the <code>JMenu</code> that delivers help to the user
   */
  @Transient
  public JMenu getHelpMenu() {
    throw new Error("getHelpMenu() not yet implemented.");
  }

  /**
   * Returns the component at the specified index.
   *
   * @param i an integer specifying the position, where 0 is first
   * @return the <code>Component</code> at the position, or <code>null</code> for an invalid index
   * @deprecated replaced by <code>getComponent(int i)</code>
   */
  @Deprecated
  public Component getComponentAtIndex(int i) {
    if (i < 0 || i >= getComponentCount()) {
      return null;
    }
    return getComponent(i);
  }

  /**
   * Returns the index of the specified component.
   *
   * @param c the <code>Component</code> to find
   * @return an integer giving the component's position, where 0 is first; or -1 if it can't be
   * found
   */
  public int getComponentIndex(Component c) {
    int ncomponents = this.getComponentCount();
    Component[] component = this.getComponents();
    for (int i = 0; i < ncomponents; i++) {
      Component comp = component[i];
      if (comp == c) {
        return i;
      }
    }
    return -1;
  }

  /**
   * Sets the currently selected component, producing a
   * a change to the selection model.
   *
   * @param sel the <code>Component</code> to select
   */
  public void setSelected(Component sel) {
    SingleSelectionModel model = getSelectionModel();
    int index = getComponentIndex(sel);
    model.setSelectedIndex(index);
  }

  /**
   * Returns true if the menu bar currently has a component selected.
   *
   * @return true if a selection has been made, else false
   */
  public boolean isSelected() {
    return selectionModel.isSelected();
  }

  /**
   * Returns true if the menu bars border should be painted.
   *
   * @return true if the border should be painted, else false
   */
  public boolean isBorderPainted() {
    return paintBorder;
  }

  /**
   * Sets whether the border should be painted.
   *
   * @param b if true and border property is not <code>null</code>, the border is painted.
   * @beaninfo bound: true attribute: visualUpdate true description: Whether the border should be
   * painted.
   * @see #isBorderPainted
   */
  public void setBorderPainted(boolean b) {
    boolean oldValue = paintBorder;
    paintBorder = b;
    firePropertyChange("borderPainted", oldValue, paintBorder);
    if (b != oldValue) {
      revalidate();
      repaint();
    }
  }

  /**
   * Paints the menubar's border if <code>BorderPainted</code>
   * property is true.
   *
   * @param g the <code>Graphics</code> context to use for painting
   * @see JComponent#paint
   * @see JComponent#setBorder
   */
  protected void paintBorder(Graphics g) {
    if (isBorderPainted()) {
      super.paintBorder(g);
    }
  }

  /**
   * Sets the margin between the menubar's border and
   * its menus. Setting to <code>null</code> will cause the menubar to
   * use the default margins.
   *
   * @param m an Insets object containing the margin values
   * @beaninfo bound: true attribute: visualUpdate true description: The space between the menubar's
   * border and its contents
   * @see Insets
   */
  public void setMargin(Insets m) {
    Insets old = margin;
    this.margin = m;
    firePropertyChange("margin", old, m);
    if (old == null || !old.equals(m)) {
      revalidate();
      repaint();
    }
  }

  /**
   * Returns the margin between the menubar's border and
   * its menus.  If there is no previous margin, it will create
   * a default margin with zero size.
   *
   * @return an <code>Insets</code> object containing the margin values
   * @see Insets
   */
  public Insets getMargin() {
    if (margin == null) {
      return new Insets(0, 0, 0, 0);
    } else {
      return margin;
    }
  }


  /**
   * Implemented to be a <code>MenuElement</code> -- does nothing.
   *
   * @see #getSubElements
   */
  public void processMouseEvent(MouseEvent event, MenuElement path[],
      MenuSelectionManager manager) {
  }

  /**
   * Implemented to be a <code>MenuElement</code> -- does nothing.
   *
   * @see #getSubElements
   */
  public void processKeyEvent(KeyEvent e, MenuElement path[], MenuSelectionManager manager) {
  }

  /**
   * Implemented to be a <code>MenuElement</code> -- does nothing.
   *
   * @see #getSubElements
   */
  public void menuSelectionChanged(boolean isIncluded) {
  }

  /**
   * Implemented to be a <code>MenuElement</code> -- returns the
   * menus in this menu bar.
   * This is the reason for implementing the <code>MenuElement</code>
   * interface -- so that the menu bar can be treated the same as
   * other menu elements.
   *
   * @return an array of menu items in the menu bar.
   */
  public MenuElement[] getSubElements() {
    MenuElement result[];
    Vector<MenuElement> tmp = new Vector<MenuElement>();
    int c = getComponentCount();
    int i;
    Component m;

    for (i = 0; i < c; i++) {
      m = getComponent(i);
      if (m instanceof MenuElement) {
        tmp.addElement((MenuElement) m);
      }
    }

    result = new MenuElement[tmp.size()];
    for (i = 0, c = tmp.size(); i < c; i++) {
      result[i] = tmp.elementAt(i);
    }
    return result;
  }

  /**
   * Implemented to be a <code>MenuElement</code>. Returns this object.
   *
   * @return the current <code>Component</code> (this)
   * @see #getSubElements
   */
  public Component getComponent() {
    return this;
  }


  /**
   * Returns a string representation of this <code>JMenuBar</code>.
   * This method
   * is intended to be used only for debugging purposes, and the
   * content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not
   * be <code>null</code>.
   *
   * @return a string representation of this <code>JMenuBar</code>
   */
  protected String paramString() {
    String paintBorderString = (paintBorder ?
        "true" : "false");
    String marginString = (margin != null ?
        margin.toString() : "");

    return super.paramString() +
        ",margin=" + marginString +
        ",paintBorder=" + paintBorderString;
  }

/////////////////
// Accessibility support
////////////////

  /**
   * Gets the AccessibleContext associated with this JMenuBar.
   * For JMenuBars, the AccessibleContext takes the form of an
   * AccessibleJMenuBar.
   * A new AccessibleJMenuBar instance is created if necessary.
   *
   * @return an AccessibleJMenuBar that serves as the AccessibleContext of this JMenuBar
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleJMenuBar();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>JMenuBar</code> class.  It provides an implementation of the
   * Java Accessibility API appropriate to menu bar user-interface
   * elements.
   * <p>
   * <strong>Warning:</strong>
   * Serialized objects of this class will not be compatible with
   * future Swing releases. The current serialization support is
   * appropriate for short term storage or RMI between applications running
   * the same version of Swing.  As of 1.4, support for long term storage
   * of all JavaBeans&trade;
   * has been added to the <code>java.beans</code> package.
   * Please see {@link java.beans.XMLEncoder}.
   */
  @SuppressWarnings("serial")
  protected class AccessibleJMenuBar extends AccessibleJComponent
      implements AccessibleSelection {

    /**
     * Get the accessible state set of this object.
     *
     * @return an instance of AccessibleState containing the current state of the object
     */
    public AccessibleStateSet getAccessibleStateSet() {
      AccessibleStateSet states = super.getAccessibleStateSet();
      return states;
    }

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.MENU_BAR;
    }

    /**
     * Get the AccessibleSelection associated with this object.  In the
     * implementation of the Java Accessibility API for this class,
     * return this object, which is responsible for implementing the
     * AccessibleSelection interface on behalf of itself.
     *
     * @return this object
     */
    public AccessibleSelection getAccessibleSelection() {
      return this;
    }

    /**
     * Returns 1 if a menu is currently selected in this menu bar.
     *
     * @return 1 if a menu is currently selected, else 0
     */
    public int getAccessibleSelectionCount() {
      if (isSelected()) {
        return 1;
      } else {
        return 0;
      }
    }

    /**
     * Returns the currently selected menu if one is selected,
     * otherwise null.
     */
    public Accessible getAccessibleSelection(int i) {
      if (isSelected()) {
        if (i != 0) {   // single selection model for JMenuBar
          return null;
        }
        int j = getSelectionModel().getSelectedIndex();
        if (getComponentAtIndex(j) instanceof Accessible) {
          return (Accessible) getComponentAtIndex(j);
        }
      }
      return null;
    }

    /**
     * Returns true if the current child of this object is selected.
     *
     * @param i the zero-based index of the child in this Accessible object.
     * @see AccessibleContext#getAccessibleChild
     */
    public boolean isAccessibleChildSelected(int i) {
      return (i == getSelectionModel().getSelectedIndex());
    }

    /**
     * Selects the nth menu in the menu bar, forcing it to
     * pop up.  If another menu is popped up, this will force
     * it to close.  If the nth menu is already selected, this
     * method has no effect.
     *
     * @param i the zero-based index of selectable items
     * @see #getAccessibleStateSet
     */
    public void addAccessibleSelection(int i) {
      // first close up any open menu
      int j = getSelectionModel().getSelectedIndex();
      if (i == j) {
        return;
      }
      if (j >= 0 && j < getMenuCount()) {
        JMenu menu = getMenu(j);
        if (menu != null) {
          MenuSelectionManager.defaultManager().setSelectedPath(null);
//                  menu.setPopupMenuVisible(false);
        }
      }
      // now popup the new menu
      getSelectionModel().setSelectedIndex(i);
      JMenu menu = getMenu(i);
      if (menu != null) {
        MenuElement me[] = new MenuElement[3];
        me[0] = JMenuBar.this;
        me[1] = menu;
        me[2] = menu.getPopupMenu();
        MenuSelectionManager.defaultManager().setSelectedPath(me);
//              menu.setPopupMenuVisible(true);
      }
    }

    /**
     * Removes the nth selected item in the object from the object's
     * selection.  If the nth item isn't currently selected, this
     * method has no effect.  Otherwise, it closes the popup menu.
     *
     * @param i the zero-based index of selectable items
     */
    public void removeAccessibleSelection(int i) {
      if (i >= 0 && i < getMenuCount()) {
        JMenu menu = getMenu(i);
        if (menu != null) {
          MenuSelectionManager.defaultManager().setSelectedPath(null);
//                  menu.setPopupMenuVisible(false);
        }
        getSelectionModel().setSelectedIndex(-1);
      }
    }

    /**
     * Clears the selection in the object, so that nothing in the
     * object is selected.  This will close any open menu.
     */
    public void clearAccessibleSelection() {
      int i = getSelectionModel().getSelectedIndex();
      if (i >= 0 && i < getMenuCount()) {
        JMenu menu = getMenu(i);
        if (menu != null) {
          MenuSelectionManager.defaultManager().setSelectedPath(null);
//                  menu.setPopupMenuVisible(false);
        }
      }
      getSelectionModel().setSelectedIndex(-1);
    }

    /**
     * Normally causes every selected item in the object to be selected
     * if the object supports multiple selections.  This method
     * makes no sense in a menu bar, and so does nothing.
     */
    public void selectAllAccessibleSelection() {
    }
  } // internal class AccessibleJMenuBar


  /**
   * Subclassed to check all the child menus.
   *
   * @since 1.3
   */
  protected boolean processKeyBinding(KeyStroke ks, KeyEvent e,
      int condition, boolean pressed) {
    // See if we have a local binding.
    boolean retValue = super.processKeyBinding(ks, e, condition, pressed);
    if (!retValue) {
      MenuElement[] subElements = getSubElements();
      for (MenuElement subElement : subElements) {
        if (processBindingForKeyStrokeRecursive(
            subElement, ks, e, condition, pressed)) {
          return true;
        }
      }
    }
    return retValue;
  }

  static boolean processBindingForKeyStrokeRecursive(MenuElement elem,
      KeyStroke ks, KeyEvent e, int condition, boolean pressed) {
    if (elem == null) {
      return false;
    }

    Component c = elem.getComponent();

    if (!(c.isVisible() || (c instanceof JPopupMenu)) || !c.isEnabled()) {
      return false;
    }

    if (c != null && c instanceof JComponent &&
        ((JComponent) c).processKeyBinding(ks, e, condition, pressed)) {

      return true;
    }

    MenuElement[] subElements = elem.getSubElements();
    for (MenuElement subElement : subElements) {
      if (processBindingForKeyStrokeRecursive(subElement, ks, e, condition, pressed)) {
        return true;
        // We don't, pass along to children JMenu's
      }
    }
    return false;
  }

  /**
   * Overrides <code>JComponent.addNotify</code> to register this
   * menu bar with the current keyboard manager.
   */
  public void addNotify() {
    super.addNotify();
    KeyboardManager.getCurrentManager().registerMenuBar(this);
  }

  /**
   * Overrides <code>JComponent.removeNotify</code> to unregister this
   * menu bar with the current keyboard manager.
   */
  public void removeNotify() {
    super.removeNotify();
    KeyboardManager.getCurrentManager().unregisterMenuBar(this);
  }


  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();
    if (getUIClassID().equals(uiClassID)) {
      byte count = JComponent.getWriteObjCounter(this);
      JComponent.setWriteObjCounter(this, --count);
      if (count == 0 && ui != null) {
        ui.installUI(this);
      }
    }

    Object[] kvData = new Object[4];
    int n = 0;

    if (selectionModel instanceof Serializable) {
      kvData[n++] = "selectionModel";
      kvData[n++] = selectionModel;
    }

    s.writeObject(kvData);
  }


  /**
   * See JComponent.readObject() for information about serialization
   * in Swing.
   */
  private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
    s.defaultReadObject();
    Object[] kvData = (Object[]) (s.readObject());

    for (int i = 0; i < kvData.length; i += 2) {
      if (kvData[i] == null) {
        break;
      } else if (kvData[i].equals("selectionModel")) {
        selectionModel = (SingleSelectionModel) kvData[i + 1];
      }
    }

  }
}
